PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
In an experimental setup, a uniform electric field of magnitude 2.5×103V/m points upward and a uniform magnetic field of magnitude 0.15T points into the page. Positive ions initially move horizontally to the right at a speed that results in no deflection. The magnetic field is then turned off while the electric field remains. Which of the following best describes the subsequent motion of the ions immediately after the magnetic field is turned off?
(a) They curve downward, accelerating opposite the electric field.
(b) They curve upward, accelerating in the direction of the electric field.
(c) They continue in a straight line at the same speed because no net force now acts on them.
(d) They spiral clockwise in the plane of the page due to the remaining electric field.